When I first began venturing into animation, I often read tales from professionals who would talk about how they're merely guides making suggestions and that their puppets live and breathe on their own... that, in essence, the animators were the puppets and the puppets were the ones in control.
For the longest time, I never understood that. I thought of puppets as inanimate objects being moved exactly as the animator saw fit.
That belief only grew as I became a computer animator. I would place the 3D character model where I wanted it to start, place it where I wanted it to end, pose out the major keyframes and tweak it until it showed a spark of life. At no point in the process did I ever feel that I wasn't in full control.
...and then I started with stop motion and it all clicked.
I'll draw storyboards, make a rough animatic, plan out the movements, pacing, the works, but, once the filming starts, all is out the window as the puppet, not me, decides what will work best. Sure, he'll still hit his marks and synch up with the audio, but I'd be lying if I said I felt like I was in control of his actions at all times.
I've learned to trust my puppet's instincts instead of forcing my own and it usually works out for the best.
I suppose I'll have to chalk it up to a mixture of 'Straight Ahead Animation' and having a physical puppet to touch, but, even after experimenting with stop motion for a few years, it's still a feeling that takes me by surprise each time... and often lets me know I'm on the right track.
I'd be curious to hear everyone else's thought, experiences, and if their puppets improv.